1: They live in different neighborhoods with different standards of living.
2: Doctors only have to work on 2 models, with all the parts in the same places. Mechanics work on 300+ models from 100 years of production. These have parts hidden in all sorts of strange places!
not really... everyone is different, thats why medication needs adjustment or change, anatomy can also be different - veins, arteries, even heart can be on the other side. People also show up in the ER with all sorts of objects hidden in a couple strange places
3: Doctors 'usually' do their work with the engine running.
4: If a doctor makes a mistake, they bury it. A mechanic's mistake will come back forever and ever!
surgeon/mechanic forgets screwdriver in a patient/car it either causes damage or not.
screwdriver causes damage/failure in
worst case surgeon loses job,license,faces million$$ lawsuit,never works again; mechanic worst case gets fired goes to work at another shop in another town.